Tree developed by NDSU issued trademark

North Dakota State University Extension
KoolKat trees have heart-shaped leaves that mature to blue-green in the summer.

The North Dakota State University-developed KoolKat Katsura Tree was issued a trademark in September 2021.

The tree was introduced in 2020 by the North Dakota Agricultural Experiment Station and the NDSU Research Foundation (NDSURF) and is the 60th new plant selection developed by the NDSU Woody Plant Improvement Program led by Todd West, NDSU Department of Plant Sciences assistant dean/professor.

A registered trademark designates a specific registered name to the plant selection and ties ownership of the registered name to NDSU, which is important for marketing and licensing NDSU releases to the commercial nursery trade. Commercial nurseries must be licensed with the NDSU Research Foundation to use NDSU’s name with the release (a specific genetic clone). This is required to legally sell the named release and also to collect royalties.

“It can take up to one year from the time the trademark application is submitted to the U.S. Patent and Trademark Office (USPTO) to be officially registered,” says West. “There are many rules involved with plant names, which limit the availability of words and phrases that can be used. If the USPTO reviewer finds that the name will cause confusion in the trade, the name can be rejected and sent back for revision.”

“This review process is as stressful and can be as time consuming as getting a research manuscript published,” says West.

Out of 60 woody plant releases, NDSU has 41 active trademarks with the USPTO.

KoolKat is a single plant seedling selection originating from a population of Cercidiphyllum japonicum acquired from the Lesny Zaklad Doswiadgzalny W. Rogowie Arboretum in Rogów, Poland. Seed was acquired in 1999 and designated as TS9946. The trees in this population were part of the NDSU Woody Plant Statewide Cooperative Evaluation Program that ran from 1987 to 2007. The KoolKat selection has been evaluated for 20 years.

KoolKat is a cold hardy tree that has survived without damage in USDA climatic zone 3a at temperatures as low as -37 degrees Fahrenheit. This single plant selection is unique in that it has early fall dormancy compared to the species, which aids in increasing the winter hardiness. All other traits are similar to the species, with cordate (heart) shaped leaves emerging reddish-purple in the spring and changing to blue-green as they mature for summer. In autumn, the leaves turn yellow to apricot in color depending on the year.

KoolKat is dioecious and is a female selection, possessing only female flowers. Mature height will be 35 to 40 feet with a canopy width of 20 to 25 feet.

Learn more about the KoolKat Katsura Tree at